Pennsylvania Democrat Uses Tried and True Playbook in Tough Race

Rep. Matt Cartwright made sure to thank a man wearing a Vietnam veteran cap for his service on a recent Saturday in his northeastern Pennsylvania district.

When the veteran identified himself as “a Trump man,” Cartwright (D-Pa.) kept the conversation going. How was the veteran’s health? How was the VA treating him? What’s his phone number? Cartwright punched the digits into his cell and called it, telling the veteran to contact him if he could ever help.

In a year when dozens of Democrats are facing potential loses in November, Cartwright is a model for how to win. His district ...